Friday, July 11, 2014

The other day, someone asked me what the difference was between bacteria which is antibiotic resistant and bacteria which are persister cells, thinking they were the same thing.

When one first hears about bacteria persisting, one often makes the assumption that must mean it's antibiotic resistant.

But there is a difference between bacteria which are antibiotic resistant and bacterial persister cells - which are antibiotic tolerant .

I'm going to provide a simple illustration (ragged as it is) to show what that difference is without getting too bogged down in terminology.

First, since many people are familiar with the term "antibiotic resistant" and have heard it in the news a lot when journalists discuss MRSA and other major bacterial infections, I'll start there, and explain what it means for bacteria to be antibiotic resistant...

What Is Antibiotic Resistance, Anyway?

When an antibiotic is used, susceptible bacteria are killed or inhibited by an antibiotic, resulting in a selective pressure for the survival of resistant strains of bacteria.

Some bacteria are naturally resistant to certain antibiotics - they just happen to have the genetic makeup and qualities which make them instantly resistant to certain antibiotics. But in other cases, bacteria develop a resistance to antibiotics through genetic mutation or acquisition of genetic material from another source.

Antibiotic resistance may take the form of a spontaneous or induced genetic mutation - that is, either a random mutation or one which arose due to changes in the bacteria's environment.

It can also occur when bacteria acquire resistance genes from other bacterial species by horizontal gene transfer via conjugation, transduction, or transformation - in other words, bacterial sex, viral sharing of DNA via bacteriophage, or acquisition of DNA from another external source.

Exposure to an antibiotic naturally selects for the survival of the organisms with the genes for resistance. A gene for antibiotic resistance may readily spread through a population of reproducing bacteria.

This is a quick and dirty diagram illustrating what antibiotic resistance looks like:

One thing to keep in mind in the illustration above is that non-resistant bacteria and drug or antibiotic resistant bacteria can exist at the same time in the same host. But eventually, all the non-resistant bacteria will die off and the antibiotic resistant bacteria will survive and reproduce, creating an entirely resistant population of bacteria.

The infection will continue to spread - unless the host's immune system is strong and can manage to kill off the antibiotic-resistant bacteria - or a different antibiotic can be found that kills them.

But some antibiotic resistant infections are so virulent and so successful, that neither antibiotics nor the host's immune system can overwhelm them.

This is catastrophic when it happens on a large scale. Right now, we are headed that way, as we are having a worldwide antibiotic resistance crisis: Too many people are contracting infections which we are having difficulty effectively treating with existing antibiotics - or in some cases we cannot treat them at all.

So, this explains what antibiotic resistant bacteria is: Bacteria which either naturally has a genetic makeup which makes it resistant to a specific antibiotic or bacteria which mutates (due to various factors) in such a way that it is more likely to survive the onslaught of antibiotics and produce a new generation of resistant bacteria.

How Are Persisters Or Persister Cells Different From Antibiotic Resistant Bacteria?

Persister cells are a small subset of a given bacterial population which are not produced by genetic mutation, nor are they resistant to a specific antibiotic by default.

Persister cells are a specific phenotype of the same bacteria. A phenotype results from the expression of an organism's genes as well as environmental factors and the interactions between the two.

When we specifically think about a phenotype in terms of people, we think of their physical characteristics - such as blue or brown eyes, curly or straight hair, and so on. Phenotypes are physical characteristics which are expressed, based on an organism's genes.

In terms of bacterial phenotypes, we can think more about size and shape, rod shaped or spiral cells, and so on. But we can also think in terms of tendencies towards dormancy, and that certain environmental factors can lead to bacteria expressing their innate tendency to go dormant.

One difference between antibiotic resistant mutants and persister cells is that, unlike mutants, cells regrown from such persistent bacteria actually remain sensitive to the antibiotic. But the entire population will not be as sensitive, and there will be a subpopulation which will be antibiotic tolerant.

Here is a simple illustration showing the difference between antibiotic resistant bacteria, and persister cells, which are antibiotic tolerant:

In the first row, the bacteria in the first dish are mostly susceptible to antibiotics, except a small number of bacteria which are resistant. Almost all bacteria die when exposed to antibiotics - leaving behind the resistant bacteria, which multiply and fill the dish. Throwing more of the same antibiotic at these bacteria will not kill them.

In the second row, we have bacteria which are also mostly susceptible to antibiotics, but a small number of bacteria are persisters. Almost all the bacteria die, and the persister cells become active and reproduce, creating a new population of bacteria of which some can still be susceptible to the same antibiotics and be killed off - but there will continue to be persister cells which could slowly multiply and survive more of the same antibiotic.

Persister cells have a phenotypic "switch" which can turn on at random or in response to environmental events. There are at least three main phenotypes of persister cells:

1) Those that reenter a normal growth phase and are quickly killed.

2) Type I persisters exit the stationary phase very slowly, in a matter of hours (if not longer) rather than minutes after getting nutritional requirements met.

Anyway, overall, the mechanisms of persisters are poorly understood, and it's only in the past several years that interest has been ignited (or actually, reignited, as it was known some cells persisted after antibiotic use in the 1940's!) in persister cells and these mechanisms are being more closely investigated.

Antibiotic Resistance And Borrelia Burgdorferi - Not So Fast?

So what about the bacteria which causes Lyme disease, Borrelia burgdorferi? Is it antibiotic resistant? Has it shown signs of going the way of staph infections and tuberculosis, by becoming increasingly resistant to the antibiotics thrown at it?

No - at least not so far. In general, there is no evidence of acquired antibiotic resistance by Borrelia burgdorferi in response to treatment.

There is evidence, however, that some isolates have different preexisting susceptibilities to different antibiotics. Borreliae are known to be naturally resistant to aminoglycosides and quinolones, such as ciprofloxacin acid and ofloxacin. There have been Borrelia burgdorferi strains grown in laboratories and clinical isolates which show resistance to erythromycin. This particular resistance was first written about in depth in a 2002 study. Strain N40 is known to be resistant to erythromycin.

Erythromycin resistance is not an issue for most people who contract Lyme disease because erythromycin is a second line antibiotic which is not used to treat Lyme disease very often. It is important to be aware of it in case a patient has an allergy to the other antibiotics which are typically given and is offered erythromycin.

A study completed in 2010 demonstrated that Borrelia burgorferi is not eradicated by tigecycline, and in this study the issue of Borrelia burgdorferi potentially having persister cells and being antibiotic tolerant was raised.

Intriguingly, the researchers who wrote about these efflux pumps in Borrelia burgdorferi stated, "Existing evidence indicates that the possible heterogeneity of B. burgdorferi may enable certain isolates to evade antimicrobial therapy and may account for the subsequent relapses suffered by some patients," and cited three papers which support this statement.

At the time of publication up to the present, though, acquired resistance to specific antibiotics in specific isolates has yet to be confirmed.

However, new research has identified that Borrelia burgdorferi does have evidence of a persister cell population in vitro.

Borrelia burgdorferi And Persister Cells Some researchers - such as Dr. Stephen Barthold, who completed the study mentioned above on the effectiveness of tigecycline to treat Lyme disease - have suspected for some time that Borrelia burgdorferi might have a persister cell population.

The issue of persistence in Lyme disease has become an oddly controversial topic, for which there is no reason - research will surely sort out what the nature of these wily spirochetes is one way or the other.

And there is a renewed interest in determining what the nature is of Borrelia burgdorferi spirochetes which have been known to survive initial antibiotic treatment in animal models, and could survive treatment in humans as well.

Recently, the CDC webcast a seminar via live streaming about government-funded studies touching on the persistence of Lyme disease spirochetes (this blog will discuss this seminar more in the near future).

But even more recently, two publications were announced which discuss Borrelia burgdorferi persister cells as well as which antibiotic compounds to which those persister cells may be at least partially if not totally susceptible.

The first publication was presented at the American Society for Microbiology conference this year (ASM2014) by Sharma et al, who are Dr. Kim Lewis' team which studies persister cells at Northeastern University. In their presentation, "Persister formation in Borrelia burgdorferi", the authors determined that 0.001% to 1% of Borrelia burgdorferi cells can survive lethal doses of various antibiotics in vitro.

If 0.001% to 1% of the cells can survive lethal doses of various antibiotics in vitro, then once you've killed off all but the persister cells, the original population will be replaced in vitro in a range of times and conditions as follows:

If only .001% of the spirochetes remain, and it takes 24 hours for each division, it will take 17 days for the bacteria to return to their original population size.

If only .001% of the spirochetes remain and it takes 12 hours for each division, it will take 8.5 days for the bacteria to return to their original population size.

If 1% of the spirochetes remain and it takes 24 hours for each division, it will take one week for the bacteria to return to their original population size.

If 1% of the spirochetes remain and it takes 12 hours for each division, it will take 3.5 days or so for the bacteria to return to their original population size.

All these are back-of-the-napkin calculations for what would happen to these bacterial persisters in vitro, provided they aren't environmentally challenged and have a stable medium; provided they don't lapse into dormancy. What exactly would happen in vivo, in the host, has yet to be clearly determined.

Antibiotic resistant bacteria is resistant due to internal or induced genetic mutation of the bacteria, or by introduction of new genetic material to the bacteria.

Persister cells have a phenotypic switch, and can become dormant randomly or due to environmental stress. All the genes the bacteria needs to do this are already there; they are not mutants. Persister cells can be susceptible to antibiotics, but a subset will be tolerant to antibiotics - and that degree of tolerance depends on which phenotype they are.

Borrelia burgdorferi do not show signs so far of acquired antibiotic resistance. But the bacteria do have natural resistance to several antibiotics, and some specific resistance based on strain.

Borrelia burgdorferi have a population of persister cells, on which further studies are needed to determine their role in the infection process and how best to address them.

Monday, May 19, 2014

This past weekend, May 16-18, many Lyme disease patients, their advocates, and organizations hit the streets, sent out tweets, and held events not only to spread awareness about Lyme disease around the world - but to be a vocal group protesting the current state of affairs regarding how the medical community manages tickborne diseases.

I admit I'm late to the game on this one, having fallen behind on some of the activities going on in the Lyme disease advocacy world and focusing more on new research, a few Lyme disease related bills making their way through state and national governments, and as usual, my own medical concerns.

This past weekend was particularly challenging while using of Twitter because I was in a position where many Lyme disease advocates were posting about various Lyme disease awareness events and, at the same time, microbiologists I follow began tweeting from a major microbiology conference which had just begun in Boston.

Now, I'm not really good at multitasking even in the best of times - but it was a serious challenge to figure out how to divide my time, focus, and energy up in order to retweet items which caught my eye during the weekend.

So I may not have split the difference that well, and for that I apologize to anyone hoping to see more of a specific type of content in my tweets and retweets. I was having a difficult time prioritizing what to post, in being mindful of my audience as well as my own interests.

At the same time, I feel pretty confident that those who organized their regional protests for the worldwide Lyme disease awareness protests were doing well at the task ahead of them and doing a better job than I can about letting everyone know why they were protesting and how many different groups around the globe were involved. Advocacy can come in many different flavors and forms, and perhaps it's even fair to say I'm not the best person at organizing protests and rousing the crowds.(I don't know, by the way, on the basis of never having tried it.)

And also I'm somewhat unnerved at the prospect. An active, outgoing role for advocacy is best left to people who are somewhat further along on their recovery from illness than I am, because they can go forth in the world with a stronger physical presence; they have the stamina to spend hours walking the pavement when I do not.

But even as I sit here at home, catching up on some rest and periodically sitting down to write this blog, I wish I had given more of my attention to this protest earlier because of its mission statement and what it says.

The home page which is the primary organizing force for these Lyme-aware activities around the world, worldwidelymediseaseprotest.blogspot.com, posted the mission statement of the worldwide protest and what protesting patients and advocates around the world say they need…

Worldwide Patients are raising awareness and protesting to highlight the need for:

1. Recognition that Lyme disease/borreliosis, and other tick-borne infections, such as Babesia, Bartonella, Rickettsia, Ehrlichia, are serious, and sometimes fatal illnesses.

2. Awareness of the fact that the transmission of tick-borne pathogens, such as borrelia, babesia, rickettsia, via blood transfusion is of global concern.

3. Agreement that Lyme disease/borreliosis should be listed as a notifiable infection. Notifiable status will aid in ensuring that the incidence and spread of this disease are monitored, a necessary precursor to determining the human suffering and socioeconomic impact of the disease.

4. Education of the healthcare sector regarding the accurate diagnosis of Lyme, which in some cases may be limited to clinical presentation due to limitations of serological testing.

*Education should ensure all doctors are familiar with the CDC caution pertaining to criteria for blood tests for Lyme: “This surveillance case definition was developed for national reporting of Lyme disease; it is NOT appropriate for clinical diagnosis...Surveillance case definitions are created for the purpose of standardization, not patient care.”

* Education that Lyme should be included as a differential diagnosis when considering other illnesses that are also reliant on subjective clinical presentation, or have no known cause. This includes, but is not limited to: Motor Neurone Disease (MND) also known as Lou Gehrig’s disease or Amyotrophic lateral sclerosis (ALS) ; Multiple Sclerosis ; Alzheimer’s; Parkinson’s disease; Sarcoidosis.

5. Education of the healthcare sector regarding affordable and effective treatment of both acute and chronic Lyme and other tick-borne infections. This includes the need to update the outdated treatment guidelines of the Infectious Diseases Society of America (IDSA) and to take into account the treatment methods of other Societies such as: The International Lyme and Associated Diseases Society (ILADS) and the German Borreliosis Society (Deutsche Borreliose-Gesellschaft : DBG)

6. Funding for research into tick-borne diseases. Including: Funding for medical research into accurate Lyme testing and treatment ; Funding for research into vectors and reservoir hosts to determine what diseases they may carry and transmit. ﻿

Thoughts on the mission statement

I agree with these statements in general: There is no argument that tickborne diseases are serious and can be fatal, that we need to be aware that they could be transmitted through blood transfusions and we don't necessarily screen for them or even have standardized high volume tests for them; that better tracking of Lyme disease suspected and confirmed cases would be helpful in getting a better estimate of cases and their socioeconomic impact, that the medical profession needs to be aware of the limitations of serological testing in diagnosing Lyme disease, that guidelines which are outdated need to be updated, and that more research needs to be conducted on Lyme disease including research that leads to improved testing and more effective treatment as well as achieving a better idea of which diseases are being carried and spread.

Phew. I need a deep breath after that paragraph.

The mission statement as outlined is a good one - a starting point, a talking point on which more discussions can be built and more meaning added to it by those who are presenting it to a crowd by sharing it online and sharing it on the streets.

I already know and understand the six items, intimately, because I have suffered with Lyme disease and Babesia, have been dealing with persisting symptoms for a long time - and after finding others in a similar situation want similar items addressed.

And a large number of people came to an agreement on what this mission statement says because they, too, have shared my experience of not having been properly treated for Lyme disease as early as we could have been and have had to live with complications due to delayed treatment - as well as being co-infected and/or possibly due to other factors we have yet to fully understand.

With this in mind, it's important for those who are not patients and advocates to understand that much of what is written is a cautionary statement, written through suffering and pain by people who have endured persisting symptoms after contracting Lyme disease who want to prevent even just one more person from having to experience the hell they have experienced.

And that would include me. I don't want anyone to experience the hell I've been through and the problems I still have.

The message to anyone healthy reading along from Lyme disease advocates to you is :

We want you to stay well. We want you to be healthy. We want you to engage in jobs you enjoy, buy a house, finish that degree, have loving relationships, raise kids, play sports, go out and about and do lots of things. All the things that - by the way - a number of us can no longer do and fear we may never achieve.

None of us would be here - either me writing this blog or these folks writing up a mission statement who are out protesting on the streets and from their computers - if we didn't each either suffer from the consequences of tickborne disease or are close to someone who has. We would be doing something else, and quite possibly doing something else our hearts yearned for, that we long dreamed about - only to have those possibilities crushed out of us due to being fatigued and enduring unpredictable cycles of dysfunction and pain.

Blood tests

… That is why we want better blood tests - ones which are effective early on, and can catch the presence of a tickborne infection before the worst symptoms set in.

We want to see those of you who are newly bitten swiftly tested with accurate tests and promptly treated so you can avoid more serious symptoms and worse, more serious persisting symptoms that disrupt your lives for months and years to come.

The way things are now, it can take 4-6 weeks after a tick bite for antibodies to Lyme disease show up from a blood test. Sometimes it can take 8 weeks or even longer.

If a patient has Lyme disease but never has a rash, the diagnosis may be missed. An early negative blood test can delay treatment. This is important because those who are treated with antibiotics early on are far less likely to experience severe symptoms and complications from Lyme disease.

And now, there is a new relapsing fever spirochete carried by the same kind of tick which carries Lyme disease - Borrelia miyamotoi. And this spirochetal disease gives you symptoms very similar to Lyme disease - yet patients with it rarely see a rash and a blood test for Lyme disease will never be positive when you're infected with this organism.

Borrelia miyamotoi is a serious infection which needs antibiotic treatment.The earlier it is diagnosed and treated, the better. In a Russian study of patients with infections with Borrelia miyamotoi, symptoms were more severe than those found in patients with Lyme disease and more patients needed hospitalization and intravenous antibiotics compared to patients with Lyme disease.

Doctor education

It's not just that better objective testing for the presence of infection with Lyme disease is needed. It is - that's true. But it's also true that what's needed are better methods of assessing patients for the possibility a tickborne disease is causing their symptoms in the first place and that tickborne diseases beyond Lyme disease also have to be taken into account.

The poor bastard who has flu-like symptoms, a migraine-like headache, high fever, and is severely fatigued who repeatedly tests negative for Lyme disease and is told it must be in his head needs to become a thing of the past; a relic.

A Lyme disease test will never be positive for Babesia and Borrelia miyamotoi here in the United States, no matter how many times you run it - and yet the patient will still be sick. Not crazy. Sick.

The same applies to someone whose initial Lyme disease serology is negative yet they appear ill after having had a tick bite. Doctors need to look for coinfections. Retest for the presence of Lyme disease antibodies later, because the first test may have been too early even at 4 weeks for that specific patient. Read the literature about comparing different labs' tests for Lyme disease serology. And when it's clear the patient doesn't have a viral illness after symptoms continue to worsen and do not progress like the typical flu; when there's no recovery coming and the chest x-ray is clear... further investigation is needed.

Doctors need to recognize this, grapple with it, and by default begin to look for a physical cause for patients' symptoms before resorting to psychiatric labels. After all, we can't all be "crazy". And if we are, then that is something our society seriously has to investigate - because either the numbers are being inflated or as a culture we are downright pathological.

(This is, by the way, not to say that every patient with flu-like symptoms, a migraine-like headache, and high fever automatically has a tickborne disease. Not all all. It's just something that should be considered in the differential diagnosis more often than it has been in the past.)

Side note:

I do not envy today's medical students, and the world they are entering as doctors. They will not only be facing the spectre of increasingly antibiotic resistant infections and the resurgence of measles and polio - they will be facing the onslaught of vector-borne diseases which are spreading to areas in which they had formerly receded or where they previously had never been. They will be facing diseases carried by mosquitoes and ticks that were previously viewed as exotic and foreign - only to find they knew no borders, and could travel here just as people and birds do.

Any awareness of Lyme disease is just that - a narrow band of awareness focusing on one disease. Looking at other potential pathogens which can infect people is important, too, and becoming a medical detective is going to become a more prominent part of the job of being a doctor. Who knows who will discover the next patient 0?

Make tickborne diseases reportable - and don't stop there

Once someone has a tickborne disease, it needs to be reportable. Both suspected and confirmed, in order to get a better estimate of the number of cases out there - but also to help form a picture of how cases present themselves based on the clinical picture.

Given that 10-20% of all patients who contract Lyme disease develop persisting symptoms after initial antibiotic treatment under existing IDSA Lyme disease panel guidelines, I would also make chronic Lyme/post treatment Lyme disease a reportable condition.

No one to my knowledge is reliably tracking this condition and the number of patients who get it. And while many patients claim they were diagnosed with chronic fatigue syndrome or fibromyalgia only to find out later on they had Lyme disease, I don't think anyone has made a point of looking back in time at all their patients' files to see if those diagnosed with chronic fatigue syndrome or fibromyalgia had a documented record of a tick bite or previous diagnosis with Lyme disease - which could very well mean what they're really seeing in front of them is a case of chronic Lyme/post treatment Lyme disease which needs to be recorded.

Is it really 10-20% of an estimated 300,000 Lyme disease cases per year in the US - around 30,000-60,000 people a year who develop chronic Lyme or post treatment Lyme disease? Or is it more? Or less? Most patients I know would scoff at the idea of fewer cases. But the truth is, we don't know, because chronic Lyme disease or post treatment Lyme disease is not reportable.

And as much as the CDC and other institutions prefer and support the use of the term "post treatment Lyme disease" or "post Lyme disease" over the usage of "chronic Lyme disease" in the US, it's not clear how often family doctors and specialists actually apply these diagnostic terms to their patients in clinical practice. Nor is it something I hear about much (though I have heard of one case of post Lyme disease syndrome as a diagnosis recently) within the Lyme disease patient community.

People with a history of a tick bite and a flu-like illness which follows and doesn't go away after initial treatment report that they were usually first diagnosed with something else after initially having Lyme disease - but not usually "post-anything" and certainly not chronic Lyme disease.

Guidelines need updating - and it's not just about chronic Lyme disease

In terms of guidelines… I'm possibly not going to have everyone jumping up and down in regards to what I write next, but I have to call it as I see it: Treatment guidelines for Lyme disease do need an overhaul, period.

They either fall short of providing effective treatment for all patients who have been affected by Lyme disease or they lack studies which demonstrate high degrees of lasting positive outcomes for all patients.

ILADS guidelines acknowledge that patients who fail initial treatment may need additional treatment and it's okay to try empiric treatment to see if it helps in an individual case. This approach may or may not help individual patients - but given some patients report marked improvement, this deserves further investigation.

While their approach is something which requires more study and validation, at this point in time, patients have few options to explore in terms of treatment. Many are desperate for relief from pain, problems with short term memory and mental focus, fatigue, and other symptoms, and it would seem logical to try more antibiotics for treatment first as they are well studied, side effects are known, and it's thought a positive response to antibiotics confirms the presence of infection.

This perspective by patients has been questioned and denounced by some researchers, who state that a positive response to antibiotics is not enough evidence that patients' infections persist and they could just be having a positive response to the anti-inflammatory effect of certain antibiotics.

No one has conducted a study on this, however. And to this day, no one has conducted studies which apply the same antibiotic treatment methods ILADS does, either. There are no objective data on what works and what doesn't work beyond case studies and individual patient reports.

And at the same time, the IDSA Lyme disease panel guidelines fall short by failing to offer any form of treatment at all, not offering any off-label treatments which may be helpful, nor are they suggesting future directions for research. Instead, their 2006 guidelines contain a long list of treatments that patients should not have including vitamin supplementation. (Nevermind that in some cases a Vitamin D deficiency may add to patients' pain and supplementation could help with symptoms. That's not mentioned here, but surely it could be included in an update?)

If patients have any persisting symptoms past their initial guidelines-based treatment, most doctors currently offer patients antidepressants, anticonvulsants, and select pain medicine to treat the symptoms. Many patients report that these treatments do not consistently provide relief, though, and in some cases they do not help at all.

But let's look at one key source of the problem: The 2006 guidelines for the treatment of Lyme disease by the IDSA are outdated, and they are partially outdated by virtue of there not being any large, new, double-blind random controlled clinical trials and/or controlled studies having been completed in the past decadewhich would shed light on how more patients could be more effectively treated.

The guidelines which the IDSA Lyme disease panel published in 2006 were largely a carbon copy of those published in 2000. Many of the cited studies in them were conducted in the late 1980s and early 1990s. The remainder of the guidelines are based on a few small clinical trials using a few months of antibiotics.

Since that time, further research on Lyme disease has raised questions about its pathogenesis and persistence in animal models, but the findings from these studies have not been directly applied to the practice of human medicine. It seems a solid translational model for all aspects of Lyme disease does not appear to be ready.

The chronic Lyme disease controversy is not the only one researchers need to investigate:

At the first mention of a tick bite, we want to be certain that one 200 mg doxycycline pill is going to be adequate prophylaxis against Lyme disease. Research by Piesman and Hojgaard in 2012 suggests one 200 mg pill may not be adequate, and even before this 2012 study, one member of the 2009 IDSA review committee suggested that the strength of the quality of the evidence to support this recommendation was too high. (The committee as a whole also recommended grading of the evidence of this guideline needs to be carefully considered.)

In early stage Lyme disease, there is documentation of there being up to a 10% treatment failure rate.

In late stage Lyme disease, the guidelines state recovery after treatment may be incomplete. Late stage patients experience lingering symptoms, too.

But surprisingly, there is no specific advice in the 2006 guidelines suggesting what to do about this and how to treat the patient, and the only later suggestion I could find independently is to give patients gabapentin for neuropathic pain.

This, to me, sounds like more effective treatment is needed for early Lyme disease as well as late stage Lyme disease - regardless of what anyone thinks about chronic Lyme disease.

As for chronic Lyme/post treatment Lyme disease:

There are persisting symptoms in 10-20% of patients who contract Lyme disease, and some of these cases display symptoms which are equal in severity to cases of osteoarthritis and congestive heart failure.

These severe cases are not the equivalent of someone with the "aches and pains of daily living" which are blithely mentioned in the 2006 Lyme disease guidelines. These are far more serious cases not to be written off - just as those who develop heartblock, autonomic system disorders, short term memory loss, moderate to severe fatigue, chronic pain, and other neurocognitive problems are not to be written off, either.

In the end, people can (and will) argue all they want about whether or not extra antibiotic treatment is a good idea. What I'm doing, independently of that, is saying point blank that regardless of that debate the current treatment approach under these guidelines isn't working for all patients. And it isn't working well for a sizable minority.

Either way, no one has conducted any new treatment study for chronic Lyme disease or post treatment Lyme disease in years - either using antibiotics or on new immune modulating drugs or even supportive treatment such as better pain management approaches.

And patients and their families and workplaces continue to pay that price, in the months and years of patients having debilitating illness, loss of income, and loss of productivity.

Research for tick-borne diseases

After all I've written in this blog since it began years ago, my main complaint, my main rant has not been addressed and it is that many years have gone by and there has been very little solid research on patients with chronic Lyme disease or post treatment Lyme disease or post Lyme (one, the other, or both) and very little solid research on potential new treatments for those suffering.

And all the concerns which are brought up, above, in the worldwide Lyme disease awareness protest mission statement are ones I share in terms of research:

We need more accurate Lyme disease testing, and to know who is actively infected and who has had infection in the past. A solid direct detection test for this purpose would be great, and lack the issues a test for antibodies does. (In the meantime, perhaps a test like Spirofind will be helpful and offer additional support for diagnosis.) Right now, with the tests commonly used, it's not always easy to determine whether someone has an active infection or not.

We need better treatment and more options for those patients with persisting symptoms. And before someone jumps in defensively and says they are against seeing patients being treated with long term antibiotics, I'd like to add here that no one - not one patient I've talked to - actually likes to be on long term antibiotics.

They are trying it because they have nothing to lose and are incredibly miserable. They are trying it because in many cases they fear they will lose a lot more than they would if they didn't try it. Their jobs. Their families. Their friends. Even their minds.

They are also trying it because there are very few treatment options available, people report improvements on it, and because antibiotics are considered a "known" factor - they are evidence-based drugs which have been clinically tested, have been used long term for various indications including acne, and their safety profile and risks are known. Beyond this, of course, anything a patient tries is either indicated as a treatment to address pain, followed by alternative medicine.

If there were more effective shorter term treatments which worked, if there were more effective pain treatments which worked - patients would be willing to try them. Just as patients are willing to try any of a number of treatments now to get some relief and get their lives back. But they'll never get a chance to try anything new and evidence-based if no one does the research required. People may argue that as long as they aren't sure what causes chronic Lyme/post treatment Lyme disease, then new treatments cannot be explored. Nonsense. There are plenty of other diseases and conditions which are not well understood for which treatment has been developed and tested. To some degree, it may be that new treatments need to be developed and tested in order to acquire more knowledge about what is causing patients' symptoms - and to understand whether or not all patients are suffering with the same condition or if there are different subgroups.

We need more research into what kind of pathogens ticks are carrying and if they are pathogenic for people. This is a harder job to do, because new tickborne viruses, bacteria, and protozoa are always being discovered. I'm not sure how one is to stay on top of tickborne diseases in particular, relative to all the other new infections which are spreading across the globe. But it is a necessary part of understanding what is happening and be preemptive about zoonoses and the spread of vectorborne disease.

I'd also like to add here that we need more research into frontline prevention. Development of a product like the Kite Patch (but a version used for ticks, not mosquitoes) and vaccines which work against multiple tickborne infections which can be used in oral bait in the wild seem to be solid ideas to develop to prevent tick bites and reduce infection in host animals.

Missing pieces:The need for better science communications on tickborne diseases in the media and public - and patient liaisons for those with persisting symptoms An additional item I would add to this mission statement - or perhaps make it two items - is that patients and the public need better science communications on tickborne diseases in the media, and also a patient liaisons who are educated, articulate, and can work to represent patients in a research and public health context (refer to PCORI for an organization which already does this kind of work).

The way Lyme disease is discussed in the media right now has to change. It's been dumbed down, the debate between two sets of doctors has been fired up in articles in order to sell papers, and the actual research being done on the disease is either seldom mentioned and sometimes when it is, important details get lost.

I'd like to see more people in public discussing Lyme disease and other tickborne infections who actually do research on it, who are familiar with the debate over whether Lyme disease can persist or not, and who are not caught up in the middle of the debate share their knowledge and questions they think need to be asked to resolve controversies over persistence. I'd also like to see more medical professionals including immunologists and pain specialists write more about what kind of novel therapies they might suggest are worth trying now which would help patients feel better and improve their quality of life on top of or instead of treatments they are already trying - and to discuss the possibility of new research.

Seeing more articles written about Lyme disease and other tickborne infections, more science blogs about Lyme disease and other tickborne infections, and more educational outreach in the form of websites and books by those educated about them who can outline the certainties and uncertainties about these diseases would go a long way towards reducing ignorance about them and provide an alternative to sites which are filled with misinformation and conspiracies.

As for patient liaisons, patients with persisting symptoms related to tickborne infections need to have greater representation in the kind of research that is being funded and what will help those who are most severely affected by tickborne disease.

As it stands, a lot of the frustration which is shared within the Lyme disease patient community is over the lack of more research on their condition and lack of communication about why there has been no patient-centered assistance from groups such as the IDSA Lyme disease guidelines panel (and if anything, some patients have been individually and collectively insulted by select members of this panel (documentation of this can be found elsewhere online)) and limited assistance and communication from those who make funding decisions for government funded Lyme disease research.

Those with persisting symptoms question why there is yet another study on erythema migrans rashes and so little research on their condition, and want to know how study selection is determined and when and how their concerns can be addressed in a research context. But according to many patients, there has been little to no positive direct communication about these matters from certain organizations such as the IDSA panel with patients and their advocates.

It is this attitude of disdain or act of avoidance of patients' concerns which many consider unprofessional and which prompts me to wish that a new panel could be elected which can better reflect patient concerns as well as represent the state of the science including uncertainties - and reduce the burgeoning weight of the history of the debate in Lyme disease.

Clearly, more positive engagement is needed between patients who suffer with persisting symptoms, their advocates, and those who wield incredible power over making decisions as to how to treat their condition and what is worthwhile research.

And before I forget: We Need Open Access Research
One frustration I and others face in trying to understand the history behind how Lyme disease is tested for, diagnosed, and treated - as well as the current sociopolitical climate involving Lyme disease research and advocacy - is that most of the peer-reviewed publications about Lyme disease, chronic Lyme disease, and post treatment Lyme disease are behind paywalls.

Some of these papers have major implications for Lyme disease patients and yet many cannot access them and learn for themselves what the arguments are between academic doctors, medical organizations, advocacy organizations, and others actually are when it comes to Lyme disease.

Often, misinformation about the content of different papers gets shared and spread amongst patients who do not have access to the original copy. From there, it's all over the internet, with facts mixed in with fiction. Was something in that paper? Wasn't it? Who knows, unless you have the $30 or more to shell out for it. (Most don't. And even if you do, 24 hours of access is not enough.)

Some publications have old data which may have been overlooked and could be useful in revisiting in order to take new directions in research, and duplicate old studies and retest hypotheses. But patients and advocates can't even access many of these papers even though they may date back as far as the mid-1980's, not long after Borrelia burgdorferi, the spirochetal bacteria which causes Lyme disease, was discovered. To me, this is ridiculous and it needs to change.

Closing comments

I agree with all that is within the mission statement and yet I think in actuality it needs to go further. The strength in a protest which has a petition or plea for certain changes to be made is improved by getting into the details more and asking for more specifics that would be useful in resolving the problems which have dogged Lyme disease patients and advocates for many years. Decades now. And I think it must be emphasized that there have been problems with the scene in Lyme disease for many years now, and nothing has changed in many ways. That's the biggest item to me really, that I'd like to protest.

Saturday, May 17, 2014

This is just a brief post with a graphic about Lyme disease prevention created for Spring/Summer 2014 for use on Twitter, Facebook, or any of a number of social media sites. Camp Other's Tick Tack Toe game rules are simple: It is won by all players crossing off all squares to help avoid tickborne disease.

Feel free to share... My only requirements are that you pass it on as it is with no further additions or subtractions - basically don't change it. Enjoy!

To review the content of the first article briefly: We discussed the fact that no human sexual transmission studies of Borrelia burgdorferi have been conducted to date and reviewed the outcomes of animal studies on contact transmission and sexual (venereal) transmission. Based on all studies which could be found, there was evidence that Borrelia burgdorferi may be transmitted between at least some animals either via exposure to infected urine or by consumption of raw milk. The possibility that animals could transmit Borrelia burgdorferi to each other via sexual intercourse has only been examined in a few controlled studies, no cases have been confirmed so far, and it remains an issue of speculation in studies where uninfected animals came in contact with infected ones and developed a positive of antibody response (and in some cases, even signs of infection).

What follows below is some notes on studies which are listed in Table 1 in "Part 2: Sexual Transmission of Lyme Disease - Is There Evidence?" as well as notes on additional papers on Borrelia burgdorferi transmission studies which were not included in that table as they were speculative and not based on controlled studies.

Additional Notes On Studies Included In Part Two's Table

The 1994 paper, "Distribution of Borrelia burgdorferi in host mice in Pennsylvania", is a study where samples are taken from ear tissue from mice from different counties around the state of Pennsylvania. When a sample was positive by darkfield microscopy and fluorescent-antibody testing, it was sent to the CDC for further evaluation.

In the discussion section of this paper, the authors state that a group tagged mice in one county which repeatedly tested negative before began to turn up positive during the winter in areas where no vector ticks had been found - and because of this, the authors speculate this group of mice may not have been infected by ticks. However, there is no evidence in their paper which confirms an alternative method of infection. Because of this, I wouldn't cite this paper to support a method of contact or sexual transmission of Lyme disease between mice. It is a mystery how one specific group of mice in Indiana County were infected during the winter.

The authors go on to speculate that maybe the raccoons are infected via urine, but also actually refer to the 1994 paper on host mice above, wondering if sexual or oral contact may be the cause for raccoons' high rate of Borrelia burgdorferi infection. There is no evidence here which confirms this method of transmission occurred in this study - it is just something the scientists are wondering about. More recent research supports the idea that Amblyomma americanum ticks are infected with other strains of Borrelia, and today raccoons in North Carolina may be infected with those - but at the time of this study, the raccoons' infections were considered unusual because the ticks collected did not appear to be full of spirochetes in general.

Relevant Reviews, Summaries, and Editorials Outside The Scope of Part Two's Table

One of the most cited papers on Borrelia, "Biology of Borrelia Species"(1986) by Dr. Alan Barbour and Dr. Stanley Hayes, quotes research on the presence of Borrelia spirochetes in urine dating back to 1938: Chung and Wei's "Studies on the transmission of relapsing fever in North China I. Observations on the mechanism of transmission of relapsing fever in man." In a short passage, they mention that "Spirochetes in the urine could enter the host through the mucous membranes of the conjunctiva, mouth, or nose". It is this early research which perhaps set the stage for stringent laboratory rules about how to handle Borrelia burgdorferi spirochetes - that and the knowledge that other spirochetes, Leptospira, could infect people through contact with urine.

In another paper not included in the table in Part 2, "Epidemiologic Studies of Lyme disease in horses and their public health significance" there was passing mention of horse bite transmitting Lyme disease to a man in 1987 in Belgium. I am fortunate to have located the case study online describing the transmission of Lyme disease via a horse bite, "Horse Reservoir for Borrelia burgdorferi?" (Lancet, Apr. 25, 1987), and read the full text. It is an interesting case, in that it describes a man who was bitten on the neck by a horse with Lyme disease who went on to develop a erythema migrans (EM) rash and additional symptoms of Lyme disease shortly thereafter. No mention of the location of the rash was made in the case study, but had it stated it was directly at the bite site it would have strengthened the case for the infection being caused by the horse bite. As it stands, the history, timing of exposure, and clinical evidence do point to the possibility that a horse bite could have given this man Lyme disease - but this appears to be a rare case as I have not found other similar case studies.

A paper from 1991, "Borrelia burgdorferi: another cause of foodborne illness?" is an editorial letter which refers to studies mentioned in the table, and was written by researchers who questioned whether or not Borrelia burgdorferi was a risk to the food supply. They mention another study from 1990, "Thermal inactivation of Borrelia burgdorferi, the cause of Lyme disease," where it was discussed that refrigerated milk at 5° C contained viable Borrelia burgdorferi after 46 daysand that high-temperature short-time (HTST) pasteurization may not kill all Borrelia burgdorferi in milk, thus raising questions as to whether the temperature should be raised and how much. The authors do not have an answer for their own questions - they only raise them for consideration.

The 1992 paper, "Lyme Borreliosis in dairy cattle" and 1994 paper, "Lyme Borreliosis in domestic animals" were not included in the table because both are overviews on Lyme disease studies on animals which refer to existing studies otherwise mentioned in the table and do not contain new experiments; references used in one paper are also used in the other. In the first paper, references to finding spirochetes in cattle milk, urine, and colostrum are cited which are mentioned in the second. In the second paper, it is mentioned that cats have been infected via experimental inoculation of B. burgdorferi by intravenous, oral, and conjunctival routes. Both papers cite other papers already listed in the table, and as such, I have not included these two papers in the table order to avoid duplication of data.

While not directly addressed in the studies above, pasteurization seems likely to reduce odds of Borrelia burgdorferi survival.

Studies listed in Table 1 indicate that spirochetes can turn up in urine, milk, and colostrum samples, but positive samples in these studies came from animals which have not been treated with antibiotics (which affect Lyme disease) and/or fluids such as raw milk which has not been pasteurized - which suggests that the possibility of human infection from consuming animal products is going to be extremely low because most meat is cooked and milk is pasteurized.

"Thermal inactivation of Borrelia burgdorferi, the cause of Lyme disease" is the only paper I've reviewed which suggests that milk should be pasteurized at a higher temperature to ensure all spirochetes are dead.

What happens to milk during pasteurization all depends on how it's pasteurized: High-temperature short-time (HTST) pasteurization is when milk is subjected to a temperature of 71.5 °C (160 °F) to 74°C (165 °F), for about 15 to 30 seconds. Low-temperature long-time treatment is when milk is pasteurized at 63 °C (145 °F) for 30 minutes. And ultra-pasteurization is when one heats milk or cream to 138 °C (280 °F) for 2 seconds to extend the refrigerated shelf life of milk from 60 to 90 days.

This of course raises the question: At what temperature does Borrelia burgdorferi die?

"In vitro cultivation of B. burgdorferi at various temperatures demonstrates that the spirochete replicates most quickly at 37 °C. An increase in temperature to 39 °C retards growth significantly, while a 24 hour exposure at 41 °C kills all spirochetes in the culture."

According to a 2008 research study by Juliet Kim, "Differential Temperature Susceptibility and Survival of Borrelia burgdorferi and Borrelia hermsii":

It would seem either a lower temperature exposure of 41 °C over a longer duration is needed to kill all spirochetes or a higher temperature at shorter duration. Pasteurization is a minimum over 10 °C higher than these temperatures where spirochetes died off - so the question becomes how long can spirochetes survive at temperatures this high? Perhaps this is an issue requiring further research.

Summary of Findings From This Three Part Series
There is not one study to date which has been conducted which provides evidence sexual transmission of Borrelia burgdorferi, the spirochete which causes Lyme disease, occurs between humans. (I am reserving discussion on the Middelveen et al study for later - and so far the abstract does not indicate it is a transmission study.)

Far as is known, there is no study to date which has been conducted which provides evidence sexual transmission of Borrelia burgdorferi occurs between animals, either - and very few controlled studies on venereal transmission in animals have been completed (Are there more than three?).

There is some evidence that at least some animals under certain circumstances may contract infection with Borrelia burgdorferi through contact in some way. The two most plausible routes appear to be through exposure to urine and ingestion of raw milk.

Studies on pasteurization of raw milk and the temperature at which Borrelia burgdorferi lead one to believe that most if not all of Borrelia burgdorferi will die when raw milk is pasteurized - but I would like an expert spirochetologist to weigh in on this, though, and cover what is posted about laboratory plating requirements.

Researchers have at times speculated that sexual transmission of Borrelia burgdorferi may occur between animals, but there has been more speculation than there have been actual controlled studies to support this hypothesis.

Some of this speculation came about after finding out uninfected contact animals exposed to infected animals developed a positive antibody response for Borrelia burgdorferi as well as signs of infection. If sexual contact between these animals occurred, it was not recorded as having been observed in the holding pen/cage.

So, to answer the question about sexual transmission of Lyme disease between humans and also between animals: So far there is no evidence that it occurs. There are also few studies which test this possibility.

To review the content of the first article briefly: We discussed three studies which are often used online to support the idea that Lyme disease could be a sexually transmitted disease between human patients. While two of those studies provided some evidence patients had spirochetal DNA in their bodily fluids, none of the studies provided evidence that Lyme disease is sexually transmitted by people. Setting aside the yet-to-be available Middelveen et al study, there are no studies to date which provide evidence that Lyme disease can be sexually transmitted in humans and there are very few studies which investigate this method of transmission in animals. We also had an introduction to Dr. Elizabeth Burgess' Lyme disease transmission studies, the criticism from Dr. Burgdorfer which they received, and took a glance at her study findings.

In Part 2 of this series, we'll be looking more closely at the results of Dr. Burgess' studies and that of other researchers on contact transmission and the potential for sexual transmission of Lyme disease in animals.

The Tally So Far: Studies On Lyme Disease Sexual Transmission And Contact Transmission

So far, I have not located any studies on Lyme disease and sexual transmission in humans, and found only a few studies about human sexual secretions containing Borrelia burgdorferi DNA.

Is this lack of research on this method of transmission in people an oversight by researchers who are more focused on observing tickborne transmission? Or has the dominant view of researchers been that based on Lyme disease's pathogenesis, human sexual transmission of Borrelia burgdorferi is highly unlikely if not impossible - so why conduct more studies on it? Either way one answers, there is very little research on different transmission methods of Lyme disease in people.

What we do have are early animal studies which were designed to investigate the nature of Lyme disease transmission through various methods - methods such as: how much more effective needle inoculation was compared to tick bites in transmitting infection; injecting mice with the urine of infected cattle to see if they would get infected; a few studies where it was hoped animals would copulate and that one could determine if sexual transmission could occur.

To date, there are more animal studies which are about the potential for contact transmission of Borrelia burgdorferi -which means any kind of contact between animals either directly or indirectly via exposure to their blood, saliva, feces, urine, milk, or colostrum - than there are studies specifically about sexual or venereal transmission. It is the results of these early animal studies which were hoped would give one a better idea of whether or not other non-tickborne methods of transmission might also be possible in people, too.

Given the wide range of data available from different animal model transmission studies over a period of nearly fifteen years, I've decided to place them into a table to view them all in one place.

In general, the study data in the table below fall under the following five categories:

Evidence of the presence or absence of Borrelia burgdorferi in different bodily fluids of animals. These are not transmission studies. These are studies which demonstrate spirochetes or spirochetal DNA can be found in various secretions, but they do not show that such spirochetes or infection can be passed on to another host animal.

Evidence that the use of needle inoculation/subcutaneous injection of infected bodily fluids from animals can transmit Borrelia burgdorferi to uninfected animals and a tick was not required.

Evidence pointing to oral inoculation as a potential route of transmission. These are studies where the researcher deliberately tried to infect an animal with Borrelia burgdorferi (or a substance assumed to contain it) either orally or oronasally, then looked at the results.

Evidence suggesting that an uninfected animal became infected somehow by being housed in the same space as an animal already infected with Borrelia burgdorferi. These studies suggest that contact transmission may have occurred because no direct action was taken by the researcher to infect the control/uninfected animal, and no ticks were deliberately introduced to the control/uninfected animal.

For the purpose of focusing discussion, the table below mostly displays information related to the possibility of oral, contact, and sexual (venereal) transmission and not much transmission data via needle inoculation (though some of the studies also focus on that method of transmission and may be mentioned in passing).

Table 1: Evidence For The Presence of Borrelia Burgdorferi Infection Via Different Forms of Inoculation and Potential Contact Transmission

Year

Publication

OralInoculation

Contact

SpirochetalDNA

Whole CellSpirochetes

AntibodyTest

Culture/
PCRStatus

1986

Experimental inoculation of dogs with Borrelia burgdorferi

N

Y

n/a

N

IFA+ n=1/1contact exposed dog

no PCRcompleted

1986

Experimentalinoculation of Peromyscus spp. with Borrelia burgdorferi:evidence of contact transmission

n= #/# number of samples or study animals infected or not infected out of the total studied

n/a not applicable to study or no data available in given paper

Notes On The Above Table

While every effort was made for this table to be comprehensive, it may not be complete. (If you know of any additional publications and data which apply, please comment below so that I may add the paper to this table.)

Note that certain papers which have been cited online pointing to different methods of contact transmission or evidence of Borrelia burgdorferi spirochetes or spirochetal DNA in bodily fluids were not included in the above table. This is because these specific papers were either review or editorial papers which cited more than one study already included in the above table, and I did not want to give the impression that additional studies were completed where the studies and findings were reproduced by another researcher. (I do, however, mention these papers in part 3 of this series on sexual transmission.)

Note also that in certain columns data is lacking or relies on older methods:

In some studies, antibody testing was not completed on animals because the research goal was to focus on finding evidence of Borrelia DNA and/or spirochetes in a given sample and not to measure antibodies in the host animal.

Immunofluorescent antibody (IFA) assay testing was the primary method of testing samples for the presence of antibodies, rather than ELISA or Western blot. This method has been considered less sensitive than others, but given studies listed use one or more monoclonal antibodies specific to Borrelia burgdorferi (such as H5332, specific to North American OspA) the positive results obtained are noteworthy.

So What Do These Studies Indicate or Suggest?1. Contact transmission of Borrelia burgdorferi could occur between specific animals under specific conditions.

While there is some evidence that some animals can be experimentally infected with Lyme disease through an oral or ocular route, it is unclear if animals end up infected through these routes in the natural world. It's important to note that dosages and the method used in a laboratory experiment may not have their parallel in real life conditions. Optimally, observing how infections occur in the wild would be best - but it is difficult to study animals in the wild to determine exactly when and how they get infected.

What the data in this table reflects is that there is some evidence to suggest that contact transmission via urine may be a concern with some animals - particularly cattle and mice. One study on ducks points to the possibility of oral transmission, though no one has duplicated it thus far or extended additional transmission research to other kinds of birds.

Based on the studies reviewed, if a form of contact transmission can occur in animals, it appears to happen inconsistently and in low numbers of animals - and so far appears to happen more frequently in specific species. Perhaps repeat studies with larger groups of animal subjects would be helpful - or perhaps they would demonstrate that contact transmission still only occurs in relatively few subjects under narrowly defined conditions. We just don't know.

There is also some evidence that certain animals are highly unlikely to contract Lyme disease via contact transmission via urine, such as Lewis rats and Syrian hamsters.

Additional autopsy studies in such cases that demonstrate where spirochetes are found in infected animals can be useful as they can indicate why spirochetes were not likely to be found in urine based on which tissues spirochetes colonized.

2. In some cases, it is not exactly clear how contact animals were infected in individual studies. All we know is they had positive antibody tests and some showed signs of infection. Based on the studies within the above table, the following studies resulted in at least a positive IFA result in a contact animal, and in some cases evidence of spirochetal infection:

Tick-raccoon associations and the potential for Lyme disease spirochete transmission in the coastal plain of North Carolina.

Of these studies, the last two listed above contained speculation by the researchers about whether or not mice and raccoons could contract Lyme disease through other methods outside of a tick bite - and neither of those two studies were completed under lab conditions and had control animals.

As for the remaining four studies, there is no indication exactly how uninfected control animals ended up with positive antibody tests and signs of infection when in the presence of infected animals. Apparently it has happened - but how and why it happened in a number of these studies even when animals are in captivity is unclear.

It is the unknown method of contact transmission in such studies which has led to speculation by others that sexual transmission may have occurred between animals. However, without a definite confirmation that sexual contact was the route of transmission, what happened remains a mystery.

We do not have documentation in a number of cases of whether or not infected and contact animals were housed together indoors or outdoors, or if they were isolated from birds or other environmental factors which may have introduced infected ticks or Borrelia burgdorferi. Without more data, it is difficult to determine whether or not animals may have been infected via a different route.

All the same, there is research above which indicates point #1 - that animals can be infected by other animals' secretions, although how often it happens and how is a good question. So far, urine and raw milk ingestion appears to be a plausible mode of transmission between some animals.

3. There haven't been many animal studies specifically focused on sexual or venereal transmission.

Based on the studies within the above table, the following studies were specifically focused on sexual or venereal transmission and their results:

Title

Sexual or Venereal Transmission?

Investigation of venereal, transplacental, and contact
transmission of the Lyme disease spirochete,Borrelia burgdorferi, in Syrian hamsters

- negative

Relative infectivity of Borrelia burgdorferi
in Lewis rats by various routes of inoculation

- negative

Lyme Borreliosis in the laboratory mouse

- negative

Of three papers where experiments were specifically designed to see if venereal transmission occurred between animals, the results of all three were negative.

Three seems like a very small number of studies, and they were only completed on rats, Syrian hamsters, and mice. If you, the reader, knows of any additional studies on sexual or venereal transmission of Lyme disease in animals which were not included here - please comment below with the title(s) and link(s) to the paper(s).

Some Researchers Weigh In On Non-Tick Methods Of Transmission

More has been said about the methods of transmission in mice than any other animal because mice are used more extensively in a lab environment for the study of Lyme disease than any other species.

"There has been no evidence of contact transmission or detection of viable spirochetes in urine of laboratory mice. Lung, bladder, and kidney are frequently infected, but spirochetes in these tissues are present in the connective tissue of the serosa, subserosa, submucosa (bladder), and periarterial connective tissue (lung, kidney), rather than lumina of tubules, ureters, bladder, or airways."

Based on his research up to that point in time, mice were not transmitting spirochetes through their urine to uninfected mice, and spirochetes which were found in autopsies were deeply embedded in connective tissue and not lining the vessels or surface of ureters, bladders, or bronchial tubes. In other words, if live spirochetes were present, they would be highly unlikely to be found in urine.

His findings differ from those of Dr. Burgess, and those of Dr. Magnarelli.

Magnarelli et al in the paper, "Detection of Borrelia burgdorferi in Urine of Peromyscus leucopus by Inhibition Enzyme-Linked Immunosorbent Assay" determined that 57 out of 87 mice had either subunits or whole cell Borrelia burgdorferi in their urine.

Despite this high number, Magnarelli et al cited their own difficulties in detecting evidence of Lyme disease infection in mice consistently:

"For more than half of the field-collected mice tested, there was concordance in the results of the serum antibody, culture, and urine analyses. Similar results were records for four of five laboratory-bred mice inoculated with B. burgdorferi. However, there were discrepancies. B. burgdorferi antigens sometimes were detected in urine from field-collected mice without supportive data from antibody assays or culture work. This was particularly noticeable in animals captured during October and November, a period after peak nymphal I. scapularis population levels had been reached."

The authors also pointed out that antibody-positive serum and titers can be low especially during early infection, successful culturing of B. burgdorferi depended partially on the number of spirochetes present in host tissues, and that occasionally, serum antibody analyses and culturing results were positive, while urine antigen test results were negative - antigens may not always be released into urine.

In 2001, we have what may have been the last published words from Dr. Burgess on contact transmission in the book, "Infectious Diseases of Wild Mammals" published by Iowa State University Press, chapter 26. Authored by Dr. Richard Brown and Dr. Elizabeth Burgess, the chapter contains this quote:

"Although direct transmission may occur in some situations, it has not been easily substantiated (Mather et al 1991) and has yet to be shown as epidemiologically important."

The authors supported the idea that direct transmission of spirochetes may occur between animals under certain circumstances - but it's not easy to provide evidence of what exactly happened and it occurs in only a very small number of cases.

More recently, in 2010, in the book, Borrelia: Molecular Biology, Host Interaction and Pathogenesis by Horizon Press, on p. 381, the most recent note on transmission stated:

"Mice are also susceptible to infection following intragastric inoculation of very high doses of B. burgdorferi N40, but there is no evidence for contact transmission (Barthold, 1991) or in utero (placental) transmission, although maternal infection may cause fetal death (Silver et al, 1995; Weis et al, 1997)."

Since our focus here is on contact, venereal, and oral transmission and not maternal/in utero (a topic worthy of a post in itself), it's notable that mice can be infected intragastrically based on Barthold's studies - though it takes high doses to do so, and it is a question how likely it is such doses would be found in nature. According to Burgess, Peromyscus are apparently susceptible to oral inoculation with B. burgdorferi, since oral infection with ~400 spirochetes resulted in sufficient spirochetemia to infect Ixodes (previously dammini) scapularis larvae.

That there has been a variety of study outcomes regarding mice, transmission, and inoculation routes leads to questions about whether or not it is not just species that matters when it comes to how Lyme disease affects the host - but also the individual genetic background of the host animal.

Could it be that the discrepancies Magnarelli et al found in their research was due in part to the presence of mice in their study group which had this genetic variant?

Future Directions

One question this raises for some reading along is how likely is it that Borrelia burgdorferi spirochetes can be found in human urine, and is there evidence of non-sexual transmission of Lyme disease between people? This is a question that will be discussed in an upcoming blog post, as there have been a number of studies on testing human urine samples for the presence of Lyme disease.

But the main question which kicked off this post is this one: Will we have any evidence in the near future that Borrelia burgdorferi can be sexually transmitted between partners?

So far, we do not, though a recent paper by Middelveen et al, "Isolation and Detection of Borrelia burgdorferi from human vaginal and seminal secretions" is the first publication to make the claim in its abstract that live motile spirochetes have been found in vaginal and seminal secretions, and that because two partners in the study share the same strain of Borrelia burgdorferi in their secretions, odds are greater than random chance that one partner passed Borrelia burgdorferi to the other.

For these claims, I currently have no evidence. And unfortunately, my ability to give the paper a thorough review is limited without access to the full text of the paper. Once the Middelveen et al paper is out of embargo and I have read the entire paper, it deserves its own future blog entry given how important this topic has become for many patients.

To sum up:Sexual transmission of tickborne diseases - is there evidence? Answer: Not so far. But existing studies to date provide evidence that oral inoculation and urine transmission may occur in a few cases in animals.

Questions For Further Discussion:

Why did different researchers have different results when it comes to the issue of contact transmission?

How much did animal species play a role in the outcome?

Why is it in a number of cases, uninfected animals exposed to infected animals had positive antibodies for Borrelia burgdorferi but were culture negative and no spirochetes could found in tissues post-mortem?

How did duration of untreated infection in the host relate to the odds of finding spirochetal DNA or a spirochete in a given sample?

How did the timing of testing of the host animal relate to the odds of finding spirochetal DNA or a spirochete in a given sample?

The next post will include notes on some of the above studies mentioned in the table and
additional studies which have been cited when mentioning transmission methods ofBorrelia burgdorferi. The temperature at which Borrelia burgdorferi dies
off will also be discussed in relationship to pasteurization.

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In the challenge to understand Lyme Disease and its co-infections, Camp Other is looking to move away from the highly controversial and politically charged divide between the Infectious Disease Society of America (IDSA) camp and the International Lyme and Associated Diseases Society (ILADS) camp. Where is this middle ground Pam Weintraub spoke of at the October 2010 Institute of Medicine Workshop? We are seeking it here at Camp Other.

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